Introduction

Fluid management is a critical aspect of patient care, especially in the inpatient medical setting. What makes fluid management both challenging and interesting is that each patient demands careful consideration of their individual fluid needs. Unfortunately, it is impossible to apply a single, perfect formula universally to all patients. However, one general principle for all patient scenarios is to replace whatever fluid is being lost as accurately as possible. These fluid losses can differ depending on patients’ medical conditions and differ by both volume and composition. For example, a patient admitted to the hospital with severe burns will have much greater fluid losses than a relatively healthy patient who is allowed nothing by mouth and awaiting a procedure. A patient admitted for dehydration from severe diarrhea might require different fluid compositions than a patient admitted in hypovolemic shock from a brisk upper gastrointestinal (GI) bleed.

An important distinction in managing fluids is differentiating between maintenance fluids and fluid replacement. Maintenance fluids should address the basic physiologic needs of the patient including both sensible and insensible fluid losses. Sensible fluid losses refer to typical routes of excretion such as urination and defecation. Insensible losses refer to other routes of fluid loss such as in sweat and from the respiratory tract. Fluid replacement goes beyond the normal physiologic losses and includes such conditions as vomiting, diarrhea, or severe cutaneous burns. One must consider these 2 categories of fluid loss separately when devising a fluid management strategy for an individual patient.

Indications

Fluid management is an essential part for any patient admitted to the hospital. If possible, it is preferable that patients take fluids enterally since this is the natural route of fluid intake. However, many patients who are sick enough needing admission to the hospital might have a reason they cannot tolerate oral intake. Alternative routes of administration such as intravenous access can deliver fluids directly to the vascular system.

There are many ways to assess a patient’s volume status to determine their fluid needs. Often, one can determine the patient’s fluid status clinically based on a variety of physical exam findings and objective data from their vital signs. Laboratory markers are helpful as adjunctive data. The following is a list of findings which can be useful in determining whether a patient is fluid depleted or volume overloaded.[1]

Vital signs

Weight: One of the most sensitive indicators of changes to the patient's volume status is their weight. Patient weight changes approximate a gold standard to determine fluid status. Unfortunately, due to differences in scales available to hospital staff, this can be a challenging target to measure. It is ideal to weigh a patient daily on the same scale to determine trends in his or her weight changes. One can see weight gain in states of fluid excess, and weight loss in states of fluid deficit. It is also helpful to look at patient records to see any recent outpatient visits before hospitalization which might provide an idea of a patient's normal baseline weight.

Heart rate: Tachycardia can represent a compensatory physiologic response to maintain perfusion in the setting of hypovolemia. This can be an early finding in compensated hypovolemic shock. However, there are many other reasons for tachycardia such as pain, fever, and anxiety.

Blood pressure: Falling blood pressure is an ominous finding in the setting of tachycardia indicating that the cardiovascular system can no longer compensate adequately for hypovolemia. Conversely, elevated blood pressures can be seen in hypervolemia.

Orthostatic vital signs: A drop of at least 20 mm Hg systolic blood pressure or 10 mm Hg diastolic blood pressure within 2 to 5 minutes of quiet standing after 5 minutes of supine rest indicates orthostatic hypotension. Dehydrated or elderly patients who have lost sensitivity in their baroreceptors in their blood vessels might display these findings.

Respiratory rate: Increased respiratory rate indicates a compensatory response to metabolic acidosis from lactic acidosis due to poor tissue perfusion. This is an early finding in hypovolemic shock.

Urine output: Expect a minimum of 1.5 mL/kg per hour in children and greater than 1 mL/kg per hour in adults. Special situations such as administration of nephrotoxic medications such as acyclovir warrant higher thresholds for urine output to minimize renal toxicity.

Physical exam findings

Capillary refill: Normally less than 2 seconds. Easy to test on fingertips and toes

Fontanelle: Sunken fontanelle on the skull of an infant suggests hypovolemia

Edema: Peripheral edema can be a sign of volume overload or third spacing of intravascular fluid

Tear production: Relevant in infants and children; Important to ask parents for their observations and evaluate the child while in the exam room

Peripheral pulses: Check brachial and femoral pulses in infants; Check radial or dorsalis pedis pulses in older patients; Can see fast and thready pulses in dehydration states

Tactile temperature of skin: Classically find cool and clammy skin found in hypovolemic shock due to peripheral vasoconstriction causing hypoperfusion of skin especially at the extremities (i.e., hands or feet)

Mucous membranes: Appreciate dry, sandpaper-like texture of the oral mucosa or tongue in states of dehydration

Jugular vein appearance: Appreciate a distended jugular vein in volume overload state; Can also be found in patients with congestive heart failure who are euvolemic but not pumping blood appropriately

Laboratory findings

BUN/creatinine: Can be elevated secondary to prerenal acute kidney injury from decreased renal blood flow due to decreased intravascular volume

Transaminases: Can see an elevation in AST or ALT due to hypoperfusion of hepatic tissue and subsequent tissue hypoxia causing hepatocyte injury, also known as “shock liver”

Hemoconcentration: Can see elevated hematocrit due to a relative abundance of red blood cells relative to intravascular fluid volume

Preparation

The pediatric population demands careful consideration of a child’s size in determining their rate of fluid maintenance. A 3-month-old infant has much different fluid needs than those of a more fully grown 8-year-old child. In many cases, a simple calculation called the 4-2-1 rule can determine the hourly rate of fluid maintenance required for a child based on his or her weight.[2] The following example shows an application of this formula.

First 10 kg = 4 mL/kg per hour

Next 10-20 kg = 2 mL/kg per hour

Any remaining weight over 20 kg = 1 mL/kg per hour

For example, a 22kg child would have the following maintenance fluid requirements.

First 10 kg = 4 mL/kg per hour x 10kg = 40 mL per hour

Next 10-20 kg = 2 mL/kg per hour x 10 kg= 20 mL per hour

Remaining 2 kg = 1 mL/kg per hour x 2 kg = 2 mL per hour

Total hourly rate = 40 + 20 + 2 = 66 mL per hour

Another commonly used formula predicts fluid needs over a 24-hour period. The following example shows an application of this formula.

First 10 kg = 100 ml/kg per day

Next 10 to 20 kg = additional 50 mL/kg per day

Any remaining weight over 20 kg = additional 20 mL/kg per day

For example, a 70-kg man would have the following maintenance fluid requirements.

First 10 kg = 100 ml/kg/day x 10 kg = 1000 mL per day

Next 10 to 20 kg = 50 ml/kg/day x 10 kg = 500 mL per day

Remaining 50 kg = 20 ml/kg/day x 50 kg = 1000 mL per day

Total fluids per day = 1000 + 500 + 1000 = 2500 mL per day

Hourly fluid rate = 2500/24 = 104 mL per hour

One must exercise caution in applying these weight-based formulae to patients who are elderly or obese.[3] Unfortunately, no standardized guidelines exist at this point to guide adult maintenance intravenous therapy. It is beyond the scope of this article to delve into the nuances of deciding between various tonicities and volumes of fluid administration. These choices demand clinical judgment based on the initial fluid status of the patient and predictions of ongoing fluid needs. The electrolyte derangements discussed below in the complications section show potential issues arising from certain fluid choices.

Technique

The strategy of managing a patient’s fluid differs depending on each patient’s clinical condition. If there can drink adequate fluid volumes by mouth, this should be the first choice. Some patient can tolerate other enteral options such as feeding tubes. IV plus oral orders are effective for those unable to meet their total daily fluid requirements enterally. Nursing staff can titrate the ratios accordingly depending on the patient’s ability to drink. Vital signs, physical exam, and adjunctive laboratory findings mentioned previously will show if each patient's fluid management strategy is appropriate. For example, a post-surgical patient with a new ileostomy might have additional fluid output from the stoma which clinicians must factor into the overall fluid management strategy.

Complications

Electrolyte Derangements

Hyponatremia

Monitor serum sodium regularly. This is more of a risk when using hypotonic solutions. Many patients admitted to the hospital have risks of baseline elevated antidiuretic hormone (ADH) release leading to volume retention and worsening hyponatremia.[4] Isotonic fluids are preferred for maintenance fluids in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Risks of hyponatremia include cerebral edema with potentially dangerous neurologic sequelae such as seizures. If significant hyponatremia develops, it is important not to correct the serum sodium too quickly to avoid the devastating neurologic complication of central pontine myelinolysis.[5]

Monitor for peripheral edema, pulmonary edema, or hepatomegaly. It is important to consider underlying cardiac dysfunction or renal failure and adjust volumes of administration accordingly. These patients might require a lower maintenance fluid rate than expected for their body weight.

Metabolic Acidosis

Normal saline is a slightly acidic solution relative to normal body pH. This can precipitate metabolic acidosis.[6] Lactated ringers solution is a closer approximation to normal body pH; however, the use of lactated ringers vs. normal saline for fluid maintenance administration often depends on availability at each hospital institution and is an evolving paradigm undergoing discussion nationally.

Clinical Significance

Understating the importance of proper fluid management is difficult. Careful consideration of each patient’s current clinical status and relevant past medical history when determining a fluid management strategy is crucial to avoid iatrogenic problems such as dehydration, volume overload, electrolyte derangements, or pH imbalances. Close communication between all members of the healthcare team can mitigate these issues.

Enhancing Healthcare Team Outcomes

Interprofessional discussion within the healthcare team can optimize proper fluid management for patients admitted to the hospital.[7] Bedside nurses often spend more time than any other healthcare member at the bedside with their patients and can provide useful assessments of patients’ volume status through documentation of vital signs and frequent visual assessments. Nurses can also be very helpful in assessing patients’ ability to tolerate enteral fluids and encouraging patients to drink by mouth if there is no NPO order which would prevent them from doing so. Nutritionists and dietitians are very helpful in determining caloric needs for patients to ensure that they meet their metabolic demand which is especially important during acute illnesses so that the body can heal properly. This is especially important in the pediatric population for infants who drink breast or formula. Total parenteral nutrition (TPN) is sometimes necessary as a temporizing measure for patients unable to take enteral fluid intake, but it comes with a variety of challenges such as the need for central venous access and risk of central line-associated bloodstream infections (CLABSI).

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

You are collecting the output and intake record for a client. The client has had the following output and intake during the last 8 hours: Output: 1,400 mL of urine. Intake: 8 oz. of orange juice, 1/2 cup of cereal, 8 oz of tea, one ham sandwich, 1/2 cup of gelatin, 1 cup of soup, 6 oz. of 2% milk, and 16 oz.of lemon soda. How many milliliters is the intake?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

A patient under your care is status post total brain injury from a significant motor vehicle crash. A provider places an order for a brand of tube feeding to infuse at 20 mL/hr for the first twelve hours and then increase to 40 mL/hr as tolerated. Free water flushes every six hours of 100 mL are to accompany tube feedings. What is the total intake for 24 hours from both the tube feeding and the free water flushes, assuming the initial rate was tolerated and no rate change is made?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Pediatric patients require close monitoring of fluid status. Daily fluid maintenance is defined as the amount of fluid a child needs in a 24-hour period. This includes oral and parenteral fluids. A daily fluid maintenance formula aids us in calculations with pediatric patients. For the first ten kilograms of body weight, how much fluid is a required?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Pediatric patients require close monitoring of fluid status. Daily fluid maintenance is defined as the amount of fluid a child needs in a twenty-four-hour period. This includes oral and parenteral fluids and plays a vital role in the fluid status of a child. A daily fluid maintenance formula aids in calculations with pediatric patients. For the first 10 kg of body weight, how much fluid is a requirement based on this method for a 35-kg child?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Pediatric patients require close monitoring of fluid status. Daily fluid maintenance defined as the amount of fluid a child needs in a twenty-four-hour period, including oral and parenteral fluids, plays a vital role in the fluid status of a child. A daily fluid maintenance formula aids us in calculations with pediatric patients. How much fluid is a daily requirement based on this method for a 35-kg child in milliliters?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Pediatric patients require close monitoring of fluid status. Daily fluid maintenance defined as the amount of fluid a child needs in a twenty-four-hour period, including oral and parenteral fluids. This plays a vital role in the fluid status of a child. A daily fluid maintenance formula aids us in calculations with pediatric patients. How much fluid is a daily requirement based on this method for a 40-kg child?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Fluid status in pediatric patients plays a vital role and requires close monitoring. Daily fluid maintenance is defined as the amount of fluid a child needs in a 24-hour period, including oral and parenteral fluids. A daily fluid maintenance formula aids one in making calculations. How much fluid is a daily requirement based on this method for a 25-kg child?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Pediatric patients require close monitoring of fluid status. A daily fluid maintenance formula aids us in calculations with pediatric patients. How much fluid is a daily requirement based on this method for a 20-kg child?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

A 65-year-old male with a 40 pack-year smoking history presents to his healthcare provider with a 5-month history of 25 pounds of weight loss, fatigue, and cough occasionally productive of bloody sputum. A chest X-ray reveals a concerning opacity in the left middle lobe of the lung. He is admitted to the hospital and undergoes further workup including laboratory studies which are notable for serum sodium of 112 mEq/L. Hypertonic saline solution is administered through his IV, and repeat electrolytes 12 hours later reveal an increase in his serum sodium to 133 mEq/L. His neurologic status declines precipitously over the next two days. Which of the following pathophysiologic mechanisms is most likely responsible for the observed clinical change?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

A 3-year-old previously healthy girl is brought to the emergency department with a 24-hour history of vomiting. Her parents state that she has been unable to keep much down and has had 5 episodes of non-bloody, non-bilious emesis. Her vital signs upon arrival reveal a temperature of 37.7 C, heart rate 133/min, blood pressure 93/52 mmHg, and respiratory rate of 25/min. Her current weight of 14.3 kg is down 0.1 kg from her well-child visit two weeks ago. On exam, she is irritable but is consoled when placed in her parent's lap and given a smartphone. She has slightly dry mucous membranes, mildly reduced skin turgor, capillary refill of approximately 3 seconds, and slightly cool extremities. What is the best initial step in the management of this patient?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

A 3-week-old previously healthy boy is brought to the emergency department with a two-day history of projectile vomiting immediately after breastfeeding. The emesis is non-bloody and non-bilious. His mother states that he has been increasingly sleepy over the past eight hours and is now unable to latch effectively. His last wet diaper was 14 hours ago. On exam, he has a soft cry when stimulated and moves his extremities slowly while being examined. His has a sunken anterior fontanelle, dry mucous membranes, tenting skin turgor, cool extremities to the touch, mottled skin, and capillary refill of approximately 5 seconds. His current weight of 4 kg is 0.8 kg less than his most recent primary care visit from five days ago. His vital signs reveal a temperature of 36.8 C, heart rate 192/min, blood pressure 60/29 mmHg, and respiratory rate 50/min. Further evaluation reveals a palpable, olive-shaped mass in the right upper quadrant of his abdomen. Definitive diagnosis is established with an abdominal ultrasound. What is the best initial step in the management of this patient?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

A 67-year-old male with a history of acute myocardial infarction and subsequent congestive heart failure (CHF) presents to the emergency department with four days of progressive dyspnea and edema. He reports that he was unable to refill his prescription medications one week ago since his car broke down, and his son has been out of town on a business trip. His exam is notable for bibasilar crackles, jugular vein distension 5 cm above the clavicle, significant abdominal ascites, and 2+ lower extremity edema up to his knees. Laboratory evaluation in the emergency department is significant for serum sodium of 131 mmol/L, brain natriuretic peptide (BNP) of 2510 pg/mL, and undetectable troponin levels. His EKG and echocardiogram are stable from 3 months ago, and chest radiography demonstrates prominent pulmonary vascular congestion and cardiomegaly. He is admitted to the hospital for intensive management of his symptoms with intravenous medication. What is the most sensitive marker to assess the effects of the therapeutic intervention during his hospitalization?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

An 8-year-old previously healthy girl is transferred to the general hospital unit from the post-anesthesia care unit (PACU) late in the evening after undergoing an uncomplicated, laparoscopic appendectomy for acute, non-perforated appendicitis. She is still sleepy from anesthesia and not interested in eating or drinking that night, so she is started on maintenance IV fluids with 5% dextrose in 0.25% sodium chloride with 20 mEq potassium. Her postoperative course over the next 48 hours is complicated by significant ileus and resultant nausea, which impairs her ability to eat or drink anything. In the morning of her third postoperative day, she complains of headache and has two episodes of emesis. On exam, she is oriented to person, but not place or time and has blurred optic disk margins. Which of the following factors is most likely responsible for the observed clinical change?

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Friedman JN,Goldman RD,Srivastava R,Parkin PC, Development of a clinical dehydration scale for use in children between 1 and 36 months of age. The Journal of pediatrics. 2004 Aug [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Neurology. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Neurology, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Neurology, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Neurology. When it is time for the Neurology board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Neurology.